Syncope or seizure: that is the question-case report of a young patient with convulsive cardioinhibitory syncope treated with cardioneuroablation.

Background: Differentiation of syncope from seizure is challenging and has therapeutic implications. Cardioinhibitory reflex syncope typically affects young patients where permanent pacing should be avoided whenever possible. Cardioneuroablation may obviate the need for a pacemaker in well-selected patients.

Case Summary: A previously healthy 24-year-old woman was referred to the emergency department after recurrent episodes of transient loss of consciousness (TLOC). The electrocardiogram (ECG) and the echocardiogram were normal. An electroencephalogram (EEG) showed intermittent, generalized pathological activity. During EEG under photostimulation, the patient developed a short-term TLOC followed by brachial myocloni, while the concurrent ECG registered a progressive bradycardia, which turned into a complete atrioventricular block and sinus arrest with asystole for 14 s. Immediately after, the patient regained consciousness without sequelae. The episode was interpreted as cardioinhibitory convulsive syncope. However, due to the pathological EEG findings, an underlying epilepsy with ictal asystole could not be fully excluded. Therefore, an antiseizure therapy was also started. After discussing the consequences of pacemaker implantation, the patient agreed to undergo a cardioneuroablation and after 72 h without complications, she was discharged home. At 10 months, the patient autonomously discontinued the antiepileptics. The follow-up EEG displayed unspecific activities without clinical correlations. An implantable loop recorder didn't show any relevant bradyarrhythmia. At 1-year follow-up, the patient remained asymptomatic and without syncopal episodes.

Discussion: Reflex syncope must be considered in the differential diagnosis of seizures. The cardioneuroablation obviated the need for a pacemaker and allowed for the withdrawal of anticonvulsants, originally started on the premise of seizure.